Mo2019 Three-Dimensional High-Resolution Manometry in the Assessment of Anal Sphincter Defects in Patients With Incontinence: Correlation With Symptom Scores and Endoanal Ultrasonography

Abstract

Carcinoma of the prostate is a significant cause of mortality and morbidity worldwide and is the most common non-cutaneous malignancy in American men. External beam radiotherapy (EBRT) for locally advanced prostate carcinoma is associated with a halving of the 10-year prostate cancer mortality. A frequent complication of EBRT is fecal incontinence, which significantly impairs quality of life for patients. Pelvic nerve damage as a result of the radiotherapy has been implicated as a possible cause of fecal incontinence. The aim of this study was to determine if fecal incontinence severity and pudendal nerve dysfunction were more commonly associated with men that had undergone EBRT for prostate cancer than in men with fecal incontinence with no history of prostate cancer or pelvic floor radiotherapy. Methods: At Flinders Medical Centre 1305 patients underwent anorectal physiology testing between January 1998 andNovember 2013. 114men were investigated for fecal incontinence with pudendal nerve terminal motor latency (PNTML) testing and anal manometry. Men with evidence of sphincter injury on endoanal ultrasound (EUS) (n=34), a missing EUS result (n=2) or who had received radiotherapy for causes other than prostate cancer (n=4) were excluded. Of the remaining 74 men, 17 had previously undergone radiotherapy for prostate carcinoma (presenting for anorectal testing on average 8.8 years post EBRT) and 57 had no reported prostate cancer. Pudendal nerve function, mean resting pressures (MRP), squeeze pressures (MSP) and Wexner incontinence scores, were compared between the two groups. Results The non-radiotherapy group (62±17 yrs; range 18-85) and a mean Wexner incontinence score of 8 ± 4 which was significantly less (p<0.005) than the mean score of 13 ± 3 in the radiotherapy group (77 ± 6 yrs; range 67-86). In the non-radiotherapy group, 21.7% had abnormal bilateral PNTML compared to 87.5% in the radiotherapy group (p<0.001, Chi-Square). 15.2% in the non-radiotherapy group had delayed bilateral or unilateral PNTML compared to 25.1% in the radiotherapy group (p<0.001). 6.5% of patients in the non-radiotherapy group had no unilateral or bilateral pudendal nerve response (no sphincter contraction in response to stimulus) compared to 62.6% in the radiotherapy group (p<0.001). MRP was 83 ± 40 cmH20 (normal range 54-124 cmH20) in the nonradiotherapy group compared to 55 ± 29 cm H20 in the radiotherapy group (p<0.05). MSP was 246 ± 74 cm H20 (normal range 179-317 cmH20) in the non-radiotherapy group compared to 190 ± 90 cm H20 in the radiotherapy group (p<0.05). Conclusions. Abnormal pudendal nerve function is associated with incontinent males who have received radiotherapy for prostate cancer. This study suggests that pelvic nerve damage as a result of radiotherapy may play a role in the fecal functional disorders experienced by many post-EBRT men.